The present invention relates to a heating apparatus utilizing microwaves which is especially suitable for generating hot air, for re-burning and purifying substances such as exhaust gas, for burning an inflammable thing and for heating objects to be heated.
Hitherto, there has been widely known a hot air electric heater with nichrome wire or a gas hot air heater using gas, etc. as a heating apparatus generating hot air.
Those hot air electric heater and gas hot air heater, however, could not easily heat to a temperature as high as 1000.degree. C. or over.
Further, there have been some apparatus for burning an object to be burned utilizing microwaves such as JP-A-4-301122 and JP-A-4-298623, etc. which mainly consist of filters, ceramics of honeycomb structure, a microwave generator and a waveguide. These apparatus are used to burn the particulates (very minute particles) included in the exhaust gas which are generated by internal combustion engines. The particulates are caught by the filter and are burned with microwaves. The filter and the honeycomb structured ceramics including the microwave absorption materials are heated by being irradiated with microwaves but not to a temperature in the vicinity of 1000.degree. C. because the usual microwave absorption materials are not stable at to such a high temperature.
The object of these apparatus is to burn the particulates (very minute parts) of the exhaust gas, which are caught by the filter, directly with microwaves. The remains or the exhaust gas not caught by the filter will be exhausted without being purified and even the particulates caught by the filter may not be burned completely because the filter is not heated to such a high temperature as 1000.degree. C. or over.